Jack Dorsey is giving almost 20% of Square to an organization serving struggling communities - Quartz

For a different take on the numbers, see Jack Dorsey is giving up at least 50% of his stake in Square to help underserved communities (VentureBeat)

"Nestled between Square’s financials in its IPO filing yesterday (Oct. 14), Dorsey revealed he had created the Start Small Foundation to invest in “artists, musicians, and local businesses, with a special focus on underserved communities around the world.” His donated shares will be available for sale in the IPO, with the proceeds to benefit the foundation.
Dorsey—who is also the CEO of Twitter, and Square’s largest shareholder with 71 million shares—has given 15 million shares to Start Small, for sale during the IPO, and pledged another 40 million in the future. “I’d rather have a smaller part of something big than a bigger part of something small,” he said in the regulatory filing. The total number of shares represents 19% of Square’s shares outstanding.
Dorsey later said in a tweet that the organization’s first investment will be in Ferguson, Missouri."

Jack Dorsey is giving almost 20% of Square to an organization serving struggling communities - Quartz